As a disk device, a magnetic disk drive includes a housing having a base and a top cover, and a rotatable magnetic disk and an actuator supporting thereon magnetic heads are arranged in the housing. As a method of improving the performance of the disk drive, a method of reducing the rotational resistance of the magnetic disk and the magnetic head by filling the housing with a low-density gas such as helium or the like, and closely sealing the housing is proposed.
In such a magnetic disk drive, the top cover is laser-welded onto the base of the housing thereby forming a hermetically-sealed housing and increasing the airtightness of the housing. This laser welding is carried out along the entire outer circumference of the top cover. Further, in order to transmit an electrical signal of the magnetic head provided inside the housing to a control circuit board provided outside the device, a connector penetrating the bottom wall of the housing is provided. In such a gas-filled magnetic disk drive described above, it is desirable that a hermetic connector be used as the aforementioned connector in order to maintain the airtightness of the housing.